February 9, 2023 — The first-ever cancellation of Alaska’s Bering Sea snow crab harvest was unprecedented and a shock to the state’s fishing industry and the communities dependent on it.
Unfortunately for that industry and those communities, those conditions are likely to be common in the future, according to several scientists who made presentations at the Alaska Marine Science Symposium held in late January.
The conditions that triggered the crash were likely warmer than any extreme possible during the preindustrial period but now can be expected in about one of every seven years, said Mike Litzow, a National Oceanic and Atmospheric scientist based in Kodiak. By the 2040s, those conditions can be expected to occur one out of every three years, he said.
Blame “borealization” for the disaster befalling snow crab, which is an Arctic species, Litzow said. That term refers to an ecosystem becoming boreal, with groups of organisms – called “taxa” by scientists – that have been south of the Arctic until recently.
“If we think about an Arctic animal at the southern edge of its range that’s exposed to really rapid warming, that leads us sort of inevitably to the concept of borealization,” said Litzow, director of NOAA Fisheries Kodiak laboratory and shellfish assessment program. “As you warm Arctic ecosystems, those systems become prone to a state change, where Arctic taxa such as snow crab become replaced by subarctic taxa that are better able to tolerate ice-free and warm conditions.”
Snow crab are dependent on the winter sea ice and the cold conditions created even after the seasonal melt, he said. While they are widely dispersed through the Bering Sea, the sweet spot for the commercial harvest – the place where the crab are big enough to be commercially valuable – is in the southeastern Bering Sea.